Afternoon Rush: From 3 To 6:30, It's A Long Hour

The term "rush hour" is nearly a century old-and it often feels like it's been that long since the daily crush lasted a merciful 60 minutes.

Any regular commuter knows that the rush hour is more ornery than ever. It's knotted with congestion, drags on for hours and infiltrates once quiet roadways.

And no expressway is immune. The Kennedy Expressway, reborn after a major reconstruction, still clogs for miles, with travel times easily hitting 60 minutes. The Ryan, Stevenson, Edens and Calumet Expressways now shoulder huge traffic loads every morning and evening.

A Tribune analysis of one major expressway, the Eisenhower, shows just how bad things have become: In just eight years, from 1986 to 1994, the afternoon rush hour on the roughly 13-mile stretch from Wolf Road to Franklin Street grew by 1 hour and 37 minutes.

The analysis of travel times in November showed that the afternoon rush on average lasted 3 hours and 22 minutes, from 3:06 p.m. to 6:28 p.m.

A variety of causes contribute to this diurnal ordeal, which continues despite new federal and state campaigns to get commuters to car-pool and take transit:

- While the population in the 11-county Chicago area rose only 1.5 percent from 1980 to 1990, the number of workers increased by more than 10 percent, according to a University of Illinois at Chicago study.

- U.S. census figures show that the number of private vehicles increased four times faster than the overall metropolitan population from 1980 to 1990, according to the study.

- The number of suburbanites driving alone to work increased by 23 percent from 1980 to 1990, federal highway statistics show.

- The number of work trips using transit dropped by about 10 percent during that period-while the mean travel time rose almost 7 percent to 28.1 minutes in 1990.

Traffic officials are able to so accurately measure when rush hour starts thanks to sensors embedded in the pavement every half-mile or so on Chicago-area expressways.

But every person's definition of a congested roadway is different. For some, it is not being able to go the speed limit. For others, it is a bumper-to-bumper backup.

The Illinois Department of Transportation defines it as when vehicles are passing over a traffic sensor 30 percent or more of the time. Roughly, that means in one hour, some 750 vehicles will travel over one lane of roadway going 30 m.p.h.

The department tracks congestion by taking the percentage of time vehicles are passing over a sensor and converting it into a complex measure called minute-miles. A minute-mile means that one mile of roadway is congested for one minute. The Tribune analysis defined the rush hour as starting or ending at the threshold of 30 or more minute-miles of congestion.

Though IDOT has congestion data for all the expressways, the Eisenhower provides one of the most accurate snapshots of how the rush hour has changed. Its data are not skewed by construction activity; it feeds directly from the suburbs into the central business district; and it is a well-established roadway.

But complex data aren't the only way to track how the Ike's rush hour has changed-commuters like Mike Garlich can tell you all about it. After all, Garlich is one of the very reasons the rush hour is so bad: He's a long-distance solo suburban commuter who travels the roads for nearly three hours a day.

"There's no question the rush hour has gotten worse," said Garlich, 49, an engineer who commutes from Naperville to the Loop. "It takes longer. There are more cars. And if there's an accident, you're really in trouble."

In 1986, when Garlich began driving into downtown on the Eisenhower, chugging his ritual carton of chocolate milk, the average rush hour began at 7:08 a.m. and ended at 8:53 a.m., according to the Tribune analysis.

In November 1994, the inbound trip on the Ike on average began at 7:23 a.m. and ended at 9:05 a.m.

While the morning rush has remained relatively constant, the afternoon commute shows the most dramatic change.

In the afternoons in 1986, Garlich joined an outbound commute that typically began at 3:48 p.m. and ended at 5:33 p.m. By 1994, the average outbound rush began at 3:06 p.m. and didn't let up until 6:28 p.m.

The afternoon rush hour showed more change because most commuters go straight to work in the morning.

But homebound commutes are more varied, with people working late or running errands that prolong their commute home and, hence, everyone else's rush hour.

The longer rush hour is also due to the suburbanization of the Chicago area, said Roy E. Lucke, director of research at Northwestern University's Traffic Institute.

"The movement of jobs and people will continue, and that will keep the rush hour growing," Lucke said.

Another key reason for the lengthening rush hour is job creation, said Siim Soot, a UIC professor of geography.